Support compiler-rt

[4ntoine]

git clone https://github.com/dylanmckay/llvm.git llvm_dylan
cd ./llvm_dylan/
cd ./tools
git clone https://github.com/llvm-mirror/clang.git clang
cd ..
cd ./projects
git clone https://github.com/llvm-mirror/compiler-rt compiler-rt
cd ..
mkdir build
cd build
../configure --prefix=/Users/asmirnov/Documents/dev/src/llvm_dylan/installed --enable-targets=avr
make -j4

getting error:

...
llvm[4]: Building Debug+Asserts Archive Library libclang.a
llvm[4]: Compiling c-index-test.c for Debug+Asserts build
llvm[4]: Linking Debug+Asserts executable c-index-test
llvm[4]: ======= Finished Linking Debug+Asserts Executable c-index-test
llvm[4]: Compiling c-arcmt-test.c for Debug+Asserts build
llvm[4]: Linking Debug+Asserts executable c-arcmt-test
llvm[4]: ======= Finished Linking Debug+Asserts Executable c-arcmt-test
make[4]: Nothing to be done for `all'.
mkdir: /Users/asmirnov/Documents/dev/src/llvm_dylan/build/Debug+Asserts/lib/clang/3.6.0/lib: File exists
warning: clang_darwin.mk: dropping arch 'i386' from lib 'eprintf' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'i386' from lib '10.4' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'x86_64' from lib '10.4' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'i386' from lib 'ios' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'x86_64' from lib 'ios' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'armv7' from lib 'ios' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'arm64' from lib 'ios' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'i386' from lib 'osx' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'x86_64' from lib 'osx' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'x86_64h' from lib 'osx' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'i386' from lib 'cc_kext' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'x86_64' from lib 'cc_kext' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'x86_64h' from lib 'cc_kext' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'armv7' from lib 'cc_kext' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'arm64' from lib 'cc_kext' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'x86_64' from lib 'cc_kext_ios5' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'armv7' from lib 'cc_kext_ios5' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'i386' from lib 'profile_osx' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'x86_64' from lib 'profile_osx' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'x86_64h' from lib 'profile_osx' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'i386' from lib 'profile_ios' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'x86_64' from lib 'profile_ios' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'armv7' from lib 'profile_ios' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'arm64' from lib 'profile_ios' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'i386' from lib 'asan_osx_dynamic' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'x86_64' from lib 'asan_osx_dynamic' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'x86_64h' from lib 'asan_osx_dynamic' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'i386' from lib 'asan_iossim_dynamic' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'x86_64' from lib 'asan_iossim_dynamic' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'i386' from lib 'ubsan_osx' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'x86_64' from lib 'ubsan_osx' (clang does not support it)
warning: clang_darwin.mk: dropping arch 'x86_64h' from lib 'ubsan_osx' (clang does not support it)
warning: clang_macho_embedded.mk: dropping arch 'armv6m' from lib 'soft_static'
warning: clang_macho_embedded.mk: dropping arch 'armv7m' from lib 'soft_static'
warning: clang_macho_embedded.mk: dropping arch 'armv7em' from lib 'soft_static'
warning: clang_macho_embedded.mk: dropping arch 'armv7' from lib 'soft_static'
warning: clang_macho_embedded.mk: dropping arch 'armv7em' from lib 'hard_static'
warning: clang_macho_embedded.mk: dropping arch 'armv7' from lib 'hard_static'
warning: clang_macho_embedded.mk: dropping arch 'i386' from lib 'hard_static'
warning: clang_macho_embedded.mk: dropping arch 'x86_64' from lib 'hard_static'
warning: clang_macho_embedded.mk: dropping arch 'armv6m' from lib 'soft_pic'
warning: clang_macho_embedded.mk: dropping arch 'armv7m' from lib 'soft_pic'
warning: clang_macho_embedded.mk: dropping arch 'armv7em' from lib 'soft_pic'
warning: clang_macho_embedded.mk: dropping arch 'armv7' from lib 'soft_pic'
warning: clang_macho_embedded.mk: dropping arch 'armv7em' from lib 'hard_pic'
warning: clang_macho_embedded.mk: dropping arch 'armv7' from lib 'hard_pic'
warning: clang_macho_embedded.mk: dropping arch 'i386' from lib 'hard_pic'
warning: clang_macho_embedded.mk: dropping arch 'x86_64' from lib 'hard_pic'
make[5]: Nothing to be done for `clang_darwin'.
make[5]: Nothing to be done for `clang_macho_embedded'.
llvm[4]: Copying runtime library darwin/eprintf to build dir
llvm[4]: Copying runtime library darwin/10.4 to build dir
llvm[4]: Copying runtime library darwin/osx to build dir
llvm[4]: Copying runtime library darwin/cc_kext to build dir
cp: /Users/asmirnov/Documents/dev/src/llvm_dylan/build/tools/clang/runtime/compiler-rt/clang_darwin/eprintf/libcompiler_rt.a: No such file or directory
cp: /Users/asmirnov/Documents/dev/src/llvm_dylan/build/tools/clang/runtime/compiler-rt/clang_darwin/10.4/libcompiler_rt.a: No such file or directory
make[4]: *** [/Users/asmirnov/Documents/dev/src/llvm_dylan/build/Debug+Asserts/lib/clang/3.6.0/lib/darwin/libclang_rt.eprintf.a] Error 1
make[4]: *** Waiting for unfinished jobs....
make[4]: *** [/Users/asmirnov/Documents/dev/src/llvm_dylan/build/Debug+Asserts/lib/clang/3.6.0/lib/darwin/libclang_rt.10.4.a] Error 1
cp: /Users/asmirnov/Documents/dev/src/llvm_dylan/build/tools/clang/runtime/compiler-rt/clang_darwin/osx/libcompiler_rt.a: No such file or directory
make[4]: *** [/Users/asmirnov/Documents/dev/src/llvm_dylan/build/Debug+Asserts/lib/clang/3.6.0/lib/darwin/libclang_rt.osx.a] Error 1
cp: /Users/asmirnov/Documents/dev/src/llvm_dylan/build/tools/clang/runtime/compiler-rt/clang_darwin/cc_kext/libcompiler_rt.a: No such file or directory
make[4]: *** [/Users/asmirnov/Documents/dev/src/llvm_dylan/build/Debug+Asserts/lib/clang/3.6.0/lib/darwin/libclang_rt.cc_kext.a] Error 1
rm /Users/asmirnov/Documents/dev/src/llvm_dylan/build/Debug+Asserts/lib/clang/3.6.0/lib/darwin/.dir /Users/asmirnov/Documents/dev/src/llvm_dylan/build/Debug+Asserts/lib/clang/3.6.0/lib/macho_embedded/.dir
make[3]: *** [compiler-rt/.makeall] Error 2
make[2]: *** [all] Error 1
make[1]: *** [clang/.makeall] Error 2
make: *** [all] Error 1

[4ntoine]

Did i miss anything?

[4ntoine]

I've removed ./projects/compiler-rt folder, reconfigured and i was able to compile it. It seems that Compiler-rt does not affect AVR target right?

[dylanmckay]

compiler-rt provides support routines for C and C++ code (see here). Much of the code is platform specific (for example, specialised floating point division functions for different platforms). The error is (probably, I haven't tried building clang with avr-llvm myself) that compiler-rt doesn't support AVR.

I'm not sure if clang will compile without compiler-rt - if it does, it's likely that you can compile some C and C++ programs but once you try to do something that depends on compiler-rt, you'll get undefined references. I've had a similar situation with GCC where there was no libgcc (equivalent to LLVM's compiler-rt) and I could compile programs although once I tried division, it failed to compile.

[dylanmckay]

Also, avr-llvm supports AVR, but clang probably does not. You can build clang with avr-llvm, but it probably won't be aware of the AVR target.

I am unsure as to how much effort it would be to add support code to clang to make use of the AVR backend, but I believe it wouldn't be that much effort. Currently I just use (the non-AVR) clang to build LLVM bitcode files, which can then be converted into AVR assembly files with llc from avr-llvm.

[4ntoine]

Ok. That's the purpose of getting Clang know about AVR target? If you can compile .ll using regular Clang we're done, right? Probably some information is lost, f.e. "progmem" attribute or anything else, so it's better to let the Clang support AVR target too...

[4ntoine]

Can you please create wiki with brief "Quick start" guide? I believe it's smth like that (?):

using regular clang:

1. clang -S -emit-llvm -c file.c -o file.ll

using avr-llc
2. llc file.ll -o file

what about libc/libc++? do they need any modifications for AVR like avr-libc for gcc?
Can we have full toolchain without using any GCC pieces needed finally?

[dylanmckay]

Probably some information is lost, i.e. "progmem" attribute or anything else

Yes, and the data layout information would be incorrect (although that wouldn't be a critical error).

So it's better to let the Clang support AVR target too

That should be a goal.

Can you please create wiki with brief "Quick start" guide

The README covers most of this, but that is a good idea - see #5

what about libc/libc++? does they need any modifications for AVR like avr-libc for gcc

libc++ depends solely on libc (I think), so if libc works, then so does libc++. The issue is that AVR can only support a subset of libc.

It should be possible to compile avr-libc (link here) with clang with modifications - clang by default will not know about the various extensions that avr-gcc has, such as built-in interrupt signal routines and attributes.

[4ntoine]

OK, that's good plan

[dylanmckay]

Closing, the issue does not really belong here. It would be nice to eventually support compiler-rt, I'll add it to the 'goals' section in the README.